In access technologies for wireless radio networks, especially for cellular wireless radio networks like WCDMA (wideband code division multiple access) and LTE (long term evolution) defined in 3GPP (third generation partnership project) and future 5G (fifth generation) systems, relay techniques are one of the ways for improving capacity and coverage in the cells. Relay scenarios can comprise stationary or mobile relay points with mobile user equipments (UE) either using a relay point or being a relay point. An exemplary relay scenario is shown in FIG. 1. FIG. 1 shows a wireless radio network 100 comprising a first and second base station 101, 102. A first cell 103 is served by the first base station 101. A second cell 104 is served by the second base station 102. Within the first cell 103 a first user equipment 105 and a second user equipment 106 are located. The first user equipment 105 is arranged closer to the first base station 101 and may therefore provide a better communication performance by relaying communication data from the second user equipment 106 than a direct communication between the second user equipment 106 and the base station 101. Therefore, as indicated by the dashed connections between the base station 101, the first user equipment 105 and the second user equipment 106, communication data from the second user equipment 106 is relayed via the first user equipment 105 to the base station 101.
In general, as implemented in current access technologies, a hand over of a voice or data connection for a user equipment using one cell, for example cell 103, to another cell, for example cell 104, is initiated by a current base station, for example base station 101, on the basis of a neighbor cell signal strength feedback from the user equipment. To be able to perform the necessary measurements on the neighboring cells, a base station scheduler is responsible to ensure that measurements can be conducted, e.g. by providing availability for measurement gaps if required by the user equipment, and the measurements are triggered when the current signal level strength as experienced or received at the user equipment decreases below a certain operator predefined threshold. In detail, for example, if the user equipment requires measurement gaps to identify and measure inter-frequency and/or inter-RAT (radio access technology) cells, the wireless radio access network must provide a single measurement gap pattern with constant gap duration for a concurrent monitoring of all frequency layers of the RATs. However, depending on the capabilities of the user equipment, the user equipment may be capable of conducting measurements while continuing communication without requiring explicit measurement gaps. Still, the network, e.g. the base station controller, is responsible to request the measurements.
In relay scenarios there may occur situations in which the signal strength at the user equipment does not fall below the operator defined threshold for neighbor cell measurement and thus a hand over may not occur, although it may be advisable to switch to another relay point or base station due to the better signal strength and load balancing in the neighboring cell. Such a scenario will be explained in the following in connection with FIG. 1.
The second user equipment 106 is connected to the first user equipment 105 which is acting as a relay point and has direct contact with the controlling first base station 101. Then, the second user equipment 106 is moving towards the second cell 104 as indicated by the arrow in FIG. 1 and is now positioned as indicated by reference sign 106′. In other words, the second user equipment 106 is entering the second cell 104 which could provide a more suitable link for communication via the second base station 102, for example due to improved end to end radio conditions, network cell load balancing, network scheduling strategies to avoid relaying and so on. However, as the signal strength to and from the first user equipment 105 is still good enough, the second user equipment 106 will not trigger any neighbor measurements and the radio network 100 will not be made aware of the fact that the second user equipment 106 is within cell 104. Hence, no handover from the first base station 101 to the second base station 102 will take place, but the communication will be relayed via the first user equipment 105 as indicated by the dashed connections between the second user equipment 106′, the first user equipment 105 and the first base station 101.
Therefore, there is a need for an improved operating of a user equipment in a wireless radio network, especially in connection with relayed communications.